1. Field of the Invention
The present invention relates to securing first and second bodies, which are mounted for relative sliding movement, in fixed relative position, and specifically relates to a lock device for securing one sash of a double-hung window in fixed position relative to the other sash of the window to prevent sliding movement therebetween.
2. Description of Prior Art
Various devices for locking windows of residential, commercial and industrial buildings are known. Objects of all such devices are to allow a person inside the building to render the device inoperative so that the window can be opened and closed to admit varying amounts of fresh air and to render the device operative to lock the window to prevent unauthorized entry from outside the building.
Various devices have also been proposed for locking conventional double-hung windows such as that shown in FIG. 1. As can be seen there, the window, generally indicated at 10, comprises a window frame 11 having vertically extending, parallel slots in which window sashes 12 and 13 are slidably mounted with respect to each other. One typical lock for this form of window includes a hand-operated latch 14 mounted on sash 13 that is rotatable to engage a catch 14a mounted on sash 12 to prevent relative slidable movement between sashes 12.
It has been found that this type of lock device does not provide sufficient security since a person seeking unauthorized entrance through the window need only break one of the window panes, turn the rotatable latch 14 to disengage it from the catch 14a, and slide one of the sashes 12 or 13 relative to frame 11 to open the window. Furthermore, this security problem associated with lock devices readily visible from outside the window is also encountered with types of windows other than the double-hung type shown in FIG. 1.
Still other lock devices have been proposed. For example, it has been suggested that a hole be drilled in each of the window sashes so that when the sashes are in the closed position, the holes are in axial alignment. A flat-head nail 15 shown in FIG. 1, having a diameter slightly less than the diameter of the aligned holes may be freely inserted into the holes to prevent sliding movement between the sashes of the window. The holes ordinarily are of sufficient depth so that only the head of the nail can be seen in FIG. 1 when inserted therein. While this type of simple lock device is an advantageous precaution and makes unauthorized entry more difficult, a person seeking such entry may still break the window, grasp the nail head and remove the nail from the holes.